Interface oxygen passivation of Al-doped HfO2 thin film for enhanced dielectric performance

Controlling the phase of HfO2-based dielectric film is a promising strategy for achieving superior dielectric properties. Although various approaches have successfully stabilized high-K tetragonal (T) phases in HfO2, intrinsic leakage currents—caused by oxygen ion migration toward the dielectric interfaces—have limited the reliable application of HfO2 dielectrics in robust transistors. Conventional methods to mitigate this issue rely on high-temperature oxidation processes after the dielectric layer, which can degrade process compatibility. In this work, we propose an alternative strategy: oxygen passivation using oxygen plasma following the deposition of T-phased HfO2. This post-atomic layer deposition treatment effectively suppresses leakage currents while enhancing the dielectric constant to 23. This study highlights the potential of this approach as a multifunctional processing strategy for realizing a low-leakage high-K dielectric layer.